Control mechanisms in the regulation of stem cells and tumor cells and their relation to cancer therapy will be studied. Androgens, 5 Beta-H steroid metabolites, nucleotides, and hyperoxia will be used to alter tumor cell and hematopoietic stem cell cycling to define their use in protection from myelo-suppression and increased sensitivity during chemotherapy and irradiation. Later, when an IND for the steroid metabolite 5 Beta-H-pregnane- 3-Beta-hydroxy-20-one has been procured, clinical observation on the potential use of this compound alone with androgenic hormones will be pursued. The regulation of bone marrow stem cells will be studied to determine protective therapy during Chemotherapy. In animal models androgens, 5 Beta-H steroid metabolites and hyperoxic will be used to alter hematopoietic sensitivity during chemotherapy and irradiation. For clinical observation continued evaluation will be made of etiocholanolone in hypoplastic and refractory anemias to gather data regarding most effective dosage schedule for bone marrow stimulation. In the initial clinical study the steroid metabolites will be given concurrently with acceptable androgen therapy. Dosage schedule for additional metabolites (5 Beta H pregnane 3 Beta hyphoxy - 20 one and 3 Beta hydroxy etiocholanolone) will be investigated to assess dosage schedule. Data is available to indicate that these steroids have excellent erythropoietic activity in animal models. The different stem cell compartments will be evaluated by the method of Till and Mc Cullough (CFU-S), Metcalf (CFU=C) and Stephenson and Axelrod (CFU-E). The effect on the cell cycling will be measured using combinations of CFU enumeration, 59 Fe incorporation into RBC and H3 thymidine uptake following interval treatment with chemotherapy steroids, nucleotides and hyperoxia.